Luminaire for hazardous atmospheres and explosion proof enclosure for power supply therefor

Abstract

A luminaire comprises a transparent enclosure tube, a cylindrical handle housing at one end of the tube, and a cylindrical cap housing at the opposite end of the tube. A light carriage within the tube comprises a unitary subassembly consisting of a rigid reflector having light bulb holders at opposite ends and a fluorescent bulb secured between the holders. The light carriage is removeable and replaceable as a unit without tools through an open end of the tube by unplugging it from and plugging it into a contact receptacle in the handle housing. Complementary plug and socket formations in the handle housing and light carriage assure alignment of bulb contacts. The housings have castellated ends engageable with detents on mounting brackets on a base to hold the luminaire and to direct light in a selected direction. The cap housing has a telescopical end section which is manually moveable against a spring to release the luminaire from the base without tools. An explosion proof enclosure for a lighting system which powers the luminaire has multiple identical explosion proof inlet and outlet openings which handle both high voltage AC circuits and low voltage DC intrinsically safe circuits. Each enclosure has thick flat metal plate end walls and a plurality of identical circular openings located side by side in the wall. Each opening has an internal surface configuration defining one side of a flame-quenching path. For AC power connections, explosion proof receptacles are fitted in some of the openings each receptacle having external surface configurations which define the other side of the flame-quenching path. For intrinsically safe circuit conductors, other openings are fitted with adaptors having identical external surface configurations defining flame-quenching paths, and the adaptors have a variety of electrical and mechanical mechanisms controlling access to the enclosure; three examples of such mechanisms are given as a solid plug, intrinsically safe receptacles, and a switch actuating plunger.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A luminaire which is readily removable and replaceable, and readily assembleable and disassembleable, comprising: a transparent enclosure tube, housing means comprising a pair of end housings connected to opposite ends of the tube, a light carriage within the tube, and a base;   said light carriage comprising a unitary subassembly consisting of a rigid, elongated reflector having light bulb holders secured at its opposite ends;   a tubular light bulb removably supported between said holders and assembleable as a unit with the light carriage;   means for energizing said light bulb comprising an electrical power input coupling means on said housing means, and electrical contact connections between the housing means and the light bulb holders and between the bulb holders and light bulb;   complementary plug and socket formations connected to and between the light carriage and housing means requiring said light carriage to be rotated to align said electrical contact connections between the housing means and the bulb holders moving the light carriage to close said contact connections;   first interengageable means being effective when engaged to secure one of said housings to the base;   second interengageable means being effective when engaged to secure the other of said housings to the base;   said first interengageable means comprising a pair of latch elements carried respectively on said one housing and on the base, one of said latch elements being movable to and from a locked position engaged with the other latch element, spring biasing means associated with said one housing urging the movable latch element toward said locked position to secure said one housing to the base while the other housing is secured to the base by the second interengageable means;   means for manually moving the movable latch element from said locked position against the bias of the spring biasing means to disengage the first interengageable means to release said one housing and enable movement of said one housing relative to the base;   said movement of said one housing relative to the base serving to automatically disengage the second interengageable means to release said other housing from the base.   
     
     
       2. A luminaire according to claim 1 in which said movable latch element is a telescopical section of said one housing and said other latch element is secured to the base, and said telescopical section is manually movable against the bias of said spring biasing means to disengage said telescopical section from said other latch element to release said one housing from the base. 
     
     
       3. A luminaire according to claim 1 in which said one housing is a cylindrical housing coaxial with said enclosure tube, and said movable latch element is an outer cylindrical section of said cylindrical housing which is telescopically carried on said cylindrical housing, said outer cylindrical section having an external circumferential rim engaged with the other latch element on the base, and said outer cylindrical section is manually movable axially against the bias of the spring biasing means to release said external circumferential rim from the other latch element. 
     
     
       4. A luminaire according to claim 1 in which the reflector extends parallel to the tubular light bulb, closely adjacent thereto, and is substantially wider than the light bulb and thereby effective to reflect light transversely past the tubular light bulb through the transparent enclosure tube. 
     
     
       5. A luminaire according to claim 1 in which a diameter of the tubular light bulb is substantially smaller than an inside diameter of the transparent enclosure tube, the tubular light bulb is positioned substantially off-center within the transparent enclosure tube, the light bulb being closest to the inside of the enclosure tube along a radius representative of the preferred direction of reflected light emission from the reflector; and the reflector is substantially wider than the diameter of the tubular light bulb, and thereby effective to reflect light transversely past the light bulb and through the transparent enclosure tube. 
     
     
       6. A luminaire according to claim 5 in which the reflector has a central mirror portion closest to a side of the light bulb which is farthest from the transparent enclosure tube, the said mirror portion having the shape of an inverted V, an apex of which is in close proximity to the light bulb whereby to reflect light bilaterally. 
     
     
       7. A luminaire according to claim 6 in which the reflector has flat, diagonal mirror surfaces along each elongated lateral margin of the reflector effective to receive light from the inverted "V" and reflect it past lateral sides of the light bulb. 
     
     
       8. A luminaire according to claim 1 in which said complementary plug and socket formations are provided between one of said end housings and a corresponding light bulb holder, and said electrical contact connections between the housing means and the light bulb holds comprises first and second sets of pin and socket contacts between the housing means and the respective ends of the tubular light bulb. 
     
     
       9. An intrinsically safe luminaire which is readily assembleable and disassembleable, comprising: a transparent enclosure tube, a cylindrical handle housing connected to one end of the tube, a cylindrical cap housing removably secured to the opposite end of the tube, and a light carriage within the tube;   said light carriage comprising a unitary subassembly consisting of a rigid elongated reflector comprising plural angularly disposed light reflective surfaces extending lengthwise thereof to reflect light past the lateral sides of a tubular light bulb and having light bulb holders secured to its opposite ends;   said tubular light bulb supported by and between said holders and being removable and assembleable as a unit with the light carriage;   said handle housing having electrical power input means connectable to an intrinsically safe D.C. electrical power source, and electrical means internally thereof for converting D.C. power from said source to AC power for energizing said light bulb;   electrical contact means interconnecting said electrical means in the handle housing and one of said light bulb holders to energize said light bulb; and   complementary plug and socket formations connected to and between the handle housing and said one light bulb holder requiring said light carriage to be moved toward the handle housing to close said electrical contact means only after the light carriage has been rotated to align said electrical contact means;   whereby the light carriage and light bulb can be removed and replaced as a unit through said opposite end of the enclosure tube after the cap housing has been removed.   
     
     
       10. A luminaire according to claim 9 in which the electrical contact means between said electrical means in the handle housing and one of said light bulb holders is a set of pin and socket contacts. 
     
     
       11. A luminaire which is readily removable and replaceable, and readily assembleable and disassembleable, comprising: a transparent enclosure tube, a pair of housings mounted over opposite ends of the tube, a light carriage supported in said housings and carrying a tubular light bulb within said enclosure tube, and an elongated mounting base plate located externally parallel to said enclosure tube;   means for connecting said light bulb to a source of electrical power through one of said housings;   first and second interengageable means being effective to secure said housings respectively to the mounting base plate;   each of said interengageable means comprising a pair of engaged latch elements carried respectively on the mounting base plate and on one of said housings to secure said luminaire positively to the mounting base plate;   one latch element in one pair associated with one of said housings being movable to and from a locked position whereat it engages the other latch element of that pair, spring biasing means associated with said one housing urging the movable latch element toward said locked position to secure said one housing to the mounting base plate while the other housing is secured to the mounting base plate by engagement of the other pair of latch elements; and   means for manually moving the movable latch element from said locked position against the bias of the spring biasing means to release said one housing and enable movement thereof relative to the mounting base plate;   said movement of said one housing relative to the base plate serving to automatically disengage the other housing from the mounting base plate.   
     
     
       12. A luminaire according to claim 11 in which the movable latch element is a telescopical section of one of said housings and said other latch element is secured to the mounting base plate, and said telescopical section is manually movable against the bias of said spring biasing means to disengage said telescopical section from said other latch element to release said one housing from the mounting base plate. 
     
     
       13. A luminaire according to claim 11 in which said one housing is a cylindrical housing coaxial with said enclosure tube, and said movable latch element is an outer cylindrical section of said cylindrical housing which is telescopically carried on said cylindrical housing, said outer cylindrical section having an external circumferential rim engaged with a corresponding latch element on the mounting base plate, and said outer cylindrical section is manually movable axially against the bias of the spring biasing means to release said external circumferential rim from the corresponding latch element on the mounting base plate. 
     
     
       14. A luminaire which is readily removable and replaceable, and readily assembleable and disassembleable, comprising: a transparent elongated enclosure tube having a central longitudinal axis, a pair of cylindrical end housings mounted over opposite ends of the tube, an elongated light carriage within the tube supported at its opposite ends by said housings, and an elongated mounting base plate extending externally parallel to the enclosure tube;   said light carriage comprising a tubular light bulb and an elongated reflector extending parallel to the light bulb;   means for connecting said light bulb to a source of electrical power through one of said end housings;   each of said cylindrical end housings having an external cylindrical rim;   a pair of brackets secured to the mounting base plate at opposite ends of said cylindrical end housings, each of said brackets having a latch element extending toward a corresponding one of said end housings and engageable with an inside surface of a respective one of said cylindrical rims to secure an associated one of said housings to said mounting base plate;   spring means associated with said base plate acting between said housings and said mounting base plate to urge them apart and take up clearance therebetween;   said luminaire being rotatable about said axis of said enclosure tube while secured to the mounting base plate by the brackets and spring means;   whereby the cylindrical end housing is adjustable about said axis to rotate the light bulb and reflector to direct light from the light bulb and reflector at a predetermined angle relative to said mounting base plate.   
     
     
       15. A luminaire according to claim 14 in which the cylindrical rim on at least one of said housings is castellated, with a plurality of circumferentially spaced notches selectively engageable with a detent on the corresponding bracket to hold the light bulb and reflector at a selected orientation to direct light in a predetermined direction relative to the mounting base plate. 
     
     
       16. A luminaire according to claim 15 in which the external cylindrical rim of another one of the cylindrical end housings is telescopically slidable along the axis of the enclosure tube, has a spring urging the rim outwardly against a corresponding bracket, and is manually movable against the spring to disengage the rim from the bracket and thereby release a corresponding housing from the mounting base plate.